// Uses a PIR sensor to detect movement, lights the LED 
// more info here: makeprojects.com/Project/PIR-Sensor-ArduinoAlarm/72/1 
// email me, John Park, at jp@jpixl.net 
// based upon: 
// PIR sensor tester by Limor Fried of Adafruit 
// tone code by michael@thegrebs.com 

int ledPin = 13;                // choose the pin for the LED 
int inputPin = 2;               // choose the input pin (for PIR sensor) 


int pirState = LOW;             // we start, assuming no motion detected 
int val = 0;                    // variable for reading the pin status 

void setup() { 

  pinMode(ledPin, OUTPUT);      // declare LED as output 
  pinMode(inputPin, INPUT);     // declare sensor as input 

  Serial.begin(9600); 

} 

void loop(){ 

  val = digitalRead(inputPin);  // read input value 


  if (val == HIGH) {            // check if the input is HIGH 

    digitalWrite(ledPin, HIGH);  // turn LED ON 
    delay(150); 

    if (pirState == LOW) { 

      // we have just turned on 
      Serial.println("Motion detected!"); 

      // We only want to print on the output change, not state 
      pirState = HIGH; 

    } 

  } else 
  { 

    digitalWrite(ledPin, LOW); // turn LED OFF 
    delay(300);     

    if (pirState == HIGH){ 

      // we have just turned off 
      Serial.println("Motion ended!"); 

      // We only want to print on the output change, not state 
      pirState = LOW;     } 

  } 

}